the house that jack built!

Karlos83

New member
May 25, 2015
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Hello, I'm writing hopefully for some ideas or advice on what I'm doing wrong here. Basically, my main speakers are bookshelf sized, wall  mounted in opposite diagonal corners and slightly towed into the room. There seems to be a problem with one of the main speakers though, and that is that if I stand up (so my ears are mid room height) and walk in front of that speaker, all the midrange frequencies seems to cancel out from that speaker dramatically, mostly leaving what you hear from the tweeter. This doesn't happen with the other speaker in the opposite corner so it's really noticeable and annoying, both speakers however sound fine throughout the rest of the room when playing together. I tried flipping the phase of this speaker on my active crossover, but if anything it only made it worse, the sound then became noticeably separated between the two main speakers and even thinner around the rest of the room. I've since towed the speaker in even further so it's now facing diagonally across the room directly towards the other speaker in the other corner. This seems to have helped somewhat, but far from 100% and there's still room for improvement in think.

Another problem I'm having is the integration of my bass speaker. Now let me just start by saying it's not a designed subwoofer, it's a 12 inch McKenzie driver in what was a full range cabinet with a tweeter (I've removed the tweeter and sealed the opening, now it's just a ported enclosure with a 12 inch driver in). Since it works and plays down to about 40hz, it was just laying around doing nothing in the spare room so I thought I'd give it a new lease on life (or try). The problem here I think, may be the driver is too big for the room size, or, its too big a difference in size compared to the 5 inch drivers in my main speakers to be integrated successfully(??). The result is that no matter how low a frequency or volume level i set the speaker to play (unless I turn it off completely of course), I can always seem to notice it's presence audibly and the sound it emits is just too strong or powerful to be perceived as emanating from the smaller main speakers. This then draws your attention to where the bass "MUST" be coming from (the biggest speaker in the room!). There's not many options for speaker placement in this awkward size and shaped room (hence the wall placement of the main speakers to begin with) and I've only had the bass speaker in one other place (facing widthways across the room and closer to one end than the other lengthways) which sounded dreadfully worse. Where it was before you would only hear bass notes in the side of the room furthest from the speaker, in front and to the near side you would hear virtually nothing but maybe an out of phase sounding rumble with a little vibration, or nothing at all. I've also tried flipping the phase switch for this speaker in its current position too, but that made it sound even more noticeable.

I would upload a picture of the room if I knew how (I'm new on the forum just today), but basically, imagine a perfectly square room that's been ruined (narrowed to a rectangle) so now it has a lengthways on which it's walls have been either obstructed by a large dominating chimney breast, or cut down to size by a pointless little square box room which is a separate room/hallway entrance to the front door. The room has a short but deep alcove where the window is and this is widthways from one external wall of the small hallway room, and extending into a smaller alcove at one end of the chimney breast (there's a TV and an arm chair in this window alcove with an old fashioned gas and electric cupboard behind the chair with my sound system on). I have a speaker mounted up high in the alcove at this side of the chimney breast (the problem speaker I've now aimed diagonally across the room to give it as big a dispersion space as possible). The wall opposite the chimney breast (the nearest wall to you as you walk into the room) is shorter than the chimney breast wall even though it's parallel to it, as it too has had quarter of its total potential length cut off by the other external wall of the hallway room (darn that thing!). The farthest wall from the point you walk into the room is a widthways wall (directly opposite the window wall), and also extends into the small alcove at the other side of the chimney breast and has a door taking up some space in one corner (did I mention all but one of the corners of the room has a door in it too?!). The bass speaker is placed with its back to this wall and facing lengthways towards the window, TV and arm chair etc) with the couch taking up the remaining space along the wall until just before the door. The final main speaker being mounted up high in the corner above the door, widthways across the room and facing the chimney breast (Phew). Took a lot of brain energy explaining that and I'm not even sure it makes any sense to anyone without a diagram to illustrate it, but that's my problems and situation i have to work with anyway. It's an old end of terraced house with really high up ceilings, i'm sure the room is longer from floor to ceiling than it is from wall to wall, and I think the oddest shaped room I've ever lived in lol. If there's a way I can add a diagram to this thread feel free to let me know, and I'll either take pics of the room or i will draw a schematic diagram and snap a shot of that.

Many thanks.
 

DocG

Well-known member
May 1, 2012
54
4
18,545
That's quite an entrance on the forum, Karlos! Welcome!

I think a diagram of the room would help quite a bit to throw light on the situation (me, I'm not a native speaker, which might not help either). It appears to be really difficult in a first post; if you reply, things should work better. Use the 'picture' button on top, like I did in this example (we like puppy-pictures a lot on here!).

inline-Pooch-Power-What-Dog-Friendly-Workplaces-Can-Do-For-Your-Business-a.jpg


From what I understand so far, you're having phase issues. Speakers are not meant to fire towards each other, cos you are more often than not closer to one speaker vs. the other; that can make them cancel out certain frequencies. And hanging them in the corners of the room changes their tonal balance. And with the bass coming from yet another direction (and a different distance to your ears), that just gets worse (more complicated). If you have no other options for locating the speakers, a single speaker solution might be best.

Can you elaborate on the exact gear (amp, speakers) you use? What's the available budget for fixing the problem?
 

Karlos83

New member
May 25, 2015
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Hello DocG and thanks. The budget is quite low at the minute because of two kids (lol) and I don't think it's worth investing much in the way of improvements to the construction of the room since me and the family are hoping to move in the near future. Nonetheless it would be nice to enjoy music while we are still here. I have actually experimented with just one main speaker and the bass speaker, and it does seem easier to find a balance between the two, and the sound is more tidy and manageable. May have to consider that an option if all else fails. My amplifiers aren't anything as fancy as those with expensive home theatre setups, my amps are 1x KAM kxr v2 (for the main speakers) and Pulse Spa300 (for the bass in mono bridge mode). A citronic cx34 for the frequency management with the LF summed to a mono left channel, and a stage line ULM 162 multi line mixer for anything I wish to play audio from. Next month I plan to add a cloud multi zone utility mixer simply to take advantage of its remote control function. That way I can stuff my sound equipment away somewhere and just control the music from the living room and nearby source. The main speakers are a pair of those skytec pub/bar installation speakers I picked up fairly cheap online (they've always sounded pretty good in commercial environments so I thought I'd give them a crack for the price). They're rated 100w max - 8ohm - 89dB sensitivity and frequency range of 50hz - 20khz. I'm not sure if the exact origin of the bass speaker, I found it in a pair that someone had thrown out in their front garden quite some years ago and I thought I take them with me. The other one was totalled on inspection when I got them home, but kept the one remaining working one. It's only now I've been able to find a use for it. As I mentioned it has a 12" McKenzie driver in it but the metal grille on the front says Q-max. The magnet on the back of the driver says 100 watts RMS 8ohm, the cabinet however says 200 watts RMS 8ohm, so I'm unsure if this was the original driver for the cabinet. Seating arrangement in the room is a pain in the backside, apart from where the couch is, anywhere else you may want to place a seat just obstructs something or other (electric fire, radiator, doors, etc). The way it's set out now actually gives the most floor space in the room with minimal obstruction to other things. I did plan to stick the TV on the wall but the plaster is cr*p on the walls and the TV is just too expensive to risk it falling from the wall if the plaster crumbles under its weight. I just about managed to get the speakers to stay up there lol. Speaking of time alignment, I was hoping to get an active crossover unit with delay function, but upon placing the order I was told by the company that they no longer have that item in stock, so they offered me the replacement citronic at a cheaper price. I didn't grumble. I'll get onto them pics now, thanks again.
 

Karlos83

New member
May 25, 2015
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Sorry, I took some photos but I seem to be having some trouble finding an option on here to upload them. I'm on a smartphone at the moment, I'm wonder if that's the problem.
 

DocG

Well-known member
May 1, 2012
54
4
18,545
Karlos83 said:
Sorry, I took some photos but I seem to be having some trouble finding an option on here to upload them. I'm on a smartphone at the moment, I'm wonder if that's the problem.

Yes, the site is carp with iThings and other smart devices...
 

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